Releasable pipe connector

ABSTRACT

The present invention relates to a releasable pipe connector comprised of upper and lower tubular members including mating lugs or threads which are interrupted along longitudinally extending spaces. The interrupted threads are arranged so that the upper and lower tubular members can be disconnected by rotating the members relative to each other, and locking means are provided for maintaining the interrupted threads of the tubular members in the engaged position until it is desired to disengage said members.

United States Patent Manson, Jr. July 22, 1975 [54] RELEASABLE PIPE CONNECTOR 3,205,948 9/!322 Preston 235/306 X 3,215,504 11 l R k 5 306 X [75] Inventor: Charles D. Manson, Jr., Duncan, oar I Okla Primary Examiner-Werner l-l. Schroeder [73] Assignee: l-lalliburton Company, Duncan, Assistant Examiner-Wayne L. Shedd Okla. Attorney, Agent, or Firm-John H. Tregoning [22] Filed: Feb. 4, 1974 [21] Appl. No.: 439,143 [57] ABSTRACT The present invention relates to a releasable pipe connector comprised of upper and lower tubular members [52] U.S. Cl.2 285/3; 285/333 including mating lugs or threads which are interrupted [5 l] It ll. Cl. F16L 37/24 along longitudinal"), extending spaces The interrupted [58] held of Search 285/3 threads are arranged so that the upper and lower tubu- 285/334, 306, 307, 308; 403/316, 31 364 l members can be disconnected by rotating the members relative to each other, and locking means [56] References (med are provided for maintaining the interrupted threads UNITED STATES PATENTS of the tubular members in the engaged position until it 2,066,956 1/1937 Williams 285/391 x is desired to disengage Said members- 2,963,l0l 12/1960 Koppl 285/391 X 3,051,244 8/1962 Litchfield 285/18 x 8 7 Drawmg F'gures RELEASABLE PIPE CONNECTOR In drilling and completing well bores which penetrate subterranean formations as well as carrying out remedial operations in such subterranean formations, it is often necessary to remotely disconnect or uncouple a pair of pipe sections in the well bore without damaging the pipe sections. For example, after drilling a well bore penetrating a producing formation, a string of casing commonly referred to as a liner is commonly lowered to the bottom of the well bore and cemented into place. In carrying out this operation, the liner is generally connected to the liner setting and cementing tools which are in turn connected to a string of pipe for lowering the liner and tools into the well bore and for conducting the cement down the well bore. During the cementing operation it is often desirable to rotate and reciprocate the liner setting tools and the lowering pipe string after which the setting tools and pipe string are disconnected to uncoupled from the liner and removed from the well bore. While releasable connector apparatus have been developed and used heretofore for disconnecting a pair of pipe sections in a well bore in such liner setting as well as other operations, such prior releasable coupling apparatus have generally been difficult to disengage or suffer from the disadvantage that they cannot be both reciprocated and rotated prior to being disengaged.

By the present invention an improved releasable pipe connector apparatus is provided which can be freely reciprocated and rotated prior to being disconnected, but which is simply and easily disconnected when desired without causing damage to either of the disconnected pipe sections.

In the drawings forming a part of this disclosure:

FIG. 1 is a sectional, elevational view of the apparatus of the present invention in the engaged and locked position;

FIG. 2 is a sectional elevational view of the apparatus of FIG. 1 in the engaged and unlocked position;

FIG. 3 is a partial sectional elevational view of the apparatus of FIGS. 1 and 2 in a disengaged position;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 1;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 1;

FIG. 6 is a sectional view taken along line 66 of FIG. 3; and

FIG. 7 is a sectional view taken along line 7-7 of FIG. 3.

Referring now to the drawings and particularly to FIGS. 1 through 3, the apparatus of the present invention is illustrated connected to a pair of pipe sections and is generally designated by the numeral 10. The apparatus 10 includes an upper tubular member 12 adapted to be connected to an upper pipe section 14 and a lower tubular member 18 adapted to be connected to a lower pipe section 20. As will be described in detail hereinbelow, the upper tubular member 12 is releasably connected and sealed to the lower tubular member 18 so that the pipe sections 14 and are rigidly held together until it is desired to disconnect them. For purposes of this disclosure, the pipe section 14 is illustrated in the form of a string of drill pipe and the upper tubular member 12 of the apparatus 10 includes a conventional threaded connection 16 for engaging the threaded lower end of the string of drill pipe. The pipe section 20 is illustrated in the form of a string of casing or liner, and the lower tubular member 18 is illustrated adapted to be connected to the casing or liner 20 by a threaded joint 22.

Referring still to FIGS. 1 through 3, the lower end portion of the upper tubular member 12 is formed of a reduced diameter and includes a plurality of interrupted lugs or threads 24. More specifically, the threads 24 are interrupted in a manner so that longitu dinally extending spaces are provided therein. Preferably, as best shown in FIG. 6, the threads 24 are interrupted so that three longitudinally extending equally spaced channels or grooves 25 are formed on the sides of the upper tubular member 22. A continuous groove 27 is disposed in the upper tubular member 12 above and adjacent the uppermost interrupted thread 24 thereof. The groove 27 extends around the periphery of the member 12 and a resilient seal member or seal ring 29 is positioned within the groove 27.

The lower tubular member 18 includes a plurality of interrupted lugs or threads 26 positioned internally within the upper portion thereof. The internal threads 26 are interrupted along longitudinally extending spaces in the same manner as the external threads 24 of the upon tubular member 12, i.e., they are preferably formed to include three longitudinally extending equally spaced channels 31 within the lower tubular member 18 as shown in FIG. 7. A sealing bore 33 is provided at the top of the lower tubular member 18 for sealingly contacting the seal member 29 of the upper tubular member 12. Thus, when the members 12 and 18 are fitted together a seal is provided therebetween by the seal member 29.

The external threads 24 of the upper tubular member 12 and the internal threads 26 of the lower tubular member 18 are formed of a length and width and are arranged so that the lower end portion of the tubular member 12 can be readily fitted into the upper internal portion of the tubular member 18 or removed therefrom when the threads 24 and 26 are disengaged, and so that the threads 24 and 26 can be engaged or disengaged by rotating the upper and lower tubular members 12 and 18 relative to each other. Any desired number of interruptions can be utilized in the threads forming longitudinally extending spaces therein. It is only necessary that the interruptions be arranged so that the threads can be engaged or disengaged by the relative rotation of the tubular members and the tubular members can be coupled or uncoupled by relative vertical movement of the tubular members when the threads are disengaged. Such interrupted thread connections are commonly termed breech block connections, a name derived from the interrupted thread used on breech loading firearms to attach the breech bolt to the rear of the rifle bore. Preferably, as illustrated in the drawings, the interrupted threads 24 and 26 are formed with counterclockwise lead on their bearing edges, i.e., the threads are pitched slightly to minimize the torque required to disengage the threads and to distribute tension loads uniformly to all threads. However, as will be understood by those skilled in the art, the thread lead can be clockwise or counterclockwise, or threads with no lead can be used.

In order to prevent accidental reengagement of the tubular members 12 and 18 after they have been disengaged by being rotated relative to one another and while they are being moved vertically apart, the lowermost interrupted threads 24 of the upper tubular member 12 are formed so that they are wider than the other threads 24 thereof. That is, as shown in FIGS. 1, 2 and 3, the lowermost threads 24 are of a greater longitudinal thickness as compared to the other threads 24 whereby the threads 24 cannot accidently engage with the threads 26 of the lower tubular member 18 when the members 12 and 18 are being moved apart.

Referring now specifically to FIGS. 1, 4 and 5, a tubular locking sleeve 28 having an upper end 32 and a lower end 38 is provided slidably disposed within the.

lower tubular member 18. The locking sleeve 28 includes one or more upwardly projecting arcuate lugs 30 positioned at the upper end 32 thereof. The lower end of the upper tubular member 12 includes one or more downwardly projecting arcuate lugs 36 for matingly engaging the upwardly projecting lugs 30 of the locking sleeve 28. That is, when the locking sleeve 28 is positioned with the upper end 32 thereof adjacent the lower end of the upper tubular member 12 so that the upwardly projecting lugs 30 of the locking sleeve matingly engage the downwardly projecting lugs 36 of the upper tubular member, the upper tubular member 12 and the locking sleeve 28 are prevented from rotating relative to each other.

As can be best seen in FIG. 5, the lower end portion 38 of the locking sleeve 28 includes a plurality of radially outwardly extending longitudinal lugs or splines 40. The splines 40 extend into mating grooves 42 disposed in the internal surface of the lower tubular member 18. The engagement of the splines 40 of the sleeve 28 with the grooves 42 of the tubular member 18 prevents the sleeve 28 from rotating within the lower tubular member 18, but allows the sleeve 28 to be moved vertically within the lower tubular member 18. As will be understood, the grooves 42 are located in the lower tubular member 18 so that when the threads 24 and 26 of the upper and lower tubular members 12 and 18 are engaged and the locking sleeve 28 is positioned with the upper end 32 thereof adjacent the lower end of the upper tubular member 12, the lugs 12 and 18 are engaged and the locking sleeve 28 is positioned with the upper end 32 thereof adjacent the lower end of the upper tubular member 12, the lugs 30 and 36 of the locking sleeve 28 and the tubular member l2-respec- 'tively are engaged and relative rotation between the tubular members 12 and I8 is prevented.

The internal portion of the locking sleeve 28 is formed of a diameter smaller than the internal diameter of the upper tubular member 12 so that seating and sealing surfaces 44 are provided at the upper end 32 of the locking sleeve 28 for receiving a release plug 48 the operation of which will be described further hereinbelow.

A plurality of shear pins 46 are preferably provided connected between the lower tubular member 18 and the locking sleeve 28 for maintaining the locking sleeve 28 at an upper location whereby the lugs 30 thereof are engaged with the lugs 36 of the upper tubular member 12 until a predetermined downward force is applied to the locking sleeve 28. However, as will be readily apparent to those skilled in the art, a variety of other means can be utilized in lieu of the shear pins 46 for holding the locking sleeve 28 at its upper location until forcibly moved downwardly, e.g., one or more coil springs can be positioned between the locking sleeve 28 and the lower tubular member 18. When the upper and lower tubular members 12 and 18 of the apparatus 10 are fitted together so that the interrupted threads 24 and 26 thereof are engaged, the locking sleeve 28 positioned whereby the lugs 30 thereof are engaged with the lugs 36 of the upper tubular member 12 and the shear pins 46 connected between the locking sleeve 28 and the tubular member 18, the upper and lower tubular members 12 and 18 are prevented from rotating relative to each other and the releasable pipe connector apparatus 10 can be freely reciprocated or rotated without causing the release or uncoupling thereof.

Referring now specifically to FIG. 2, in operation of the releasable pipe connector 10, when it is desired to uncouple or disconnect the pipe sections connected together thereby, a conventional release plug 48 is caused to be lowered through the upper pipe section 14 and the upper tubular member 12 into seating engagement with the locking sleeve 28. The release plug 48 can take a variety of forms and can be pumped through the pipe section 14 or lowered on a wire line into contact with the locking sleeve 28. The release plug 48 preferably includes a seating surface 50 of a diameter and shape such that when the release plug 48 contacts the locking sleeve 28 a seal is provided between the seating surface 44 of the locking sleeve 28 and the surface 50 of the release plug 48. A resilient seal member 49 is preferably disposed in a groove provided in the nose of the release plug 48 for providing a further seal between the release plug 48 and the locking sleeve 28. Further, as will be understood by those skilled in the art, the release plug 48 can include latching means for maintaining the release plug 48 engaged with the locking sleeve 28 after the pipe connector 10 has been uncoupled. This is particularly desirable when using the connector 10 in liner cementing operations and the like in that the continuous engagement of the release plug 48 with the locking sleeve 28 prevents cement from entering the liner.

Once the release plug 48 has been seated against the locking sleeve 28 pressure is exerted thereon by pumping against the release plug 48 or by other conventional means so that the release plug 48 is driven downwardly against the locking sleeve 28 with a force sufficient to shear the shear pins 46 and move the locking sleeve 28 downwardly within the lower tubular member 18 from its upper engaged or locked location (FIG. 1) to a lower unlocked location (FIG. 2). The movement of the locking sleeve 28 to the lower location disengages the lugs 30 thereof from the lugs 36 of the upper tubular member 12. When the locking sleeve 28 has been so disengaged, the upper pipe section 14 and the upper tubular member 12 are rotated relative to the lower pipe section 20 and the lower tubular member 18 whereby the interrupted threads 24 and 26 of the tubular members are disengaged. The upper pipe section 14 and upper tubular member 12 are then moved upwardly relative to the lower tubular member 18 and lower pipe section 20 as shown in FIG. 3 to complete the release or disconnection of the connector apparatus 10.

Thus, the present invention is well adapted to attain the ends and advantages mentioned as well as those inherent therein. While presently preferred embodiments of the invention have been described for purposes of this disclosure, numerous changes can be made which will readily suggest themselves to those skilled in the art and which are encompassed within the spirit of this invention as defined by the appended claims.

5 6 What is claimed is: 4. The releasable pipe connector of claim 3 wherein 1. A releasable breech block pipe connector, for conthe means for maintaining said locking sleeve means at necting a pipe section thereabove to a pipe section said upper location until a predetermined downward therebelow, which comprises: force is applied thereto comprises at least one shear pin a. an upper tubular breech block member including: 5 connected between said locking sleeve means and said i. means for connecting an upper end of said upper lower b l r m mbertubular breech blo k m b r t th i ti 5. A releasable pipe connection which comprises: thereabove; and a. an upper tubular member, including:

ii. interrupted threads positioned at the lower end means connecting an pp elld of Sald PP thereof, said threads being interrupted along lonl bulal member to 3 P p Section lhel'eabove; gitudinally t di Spaces; ii. at least one downwardly projecting lug attached b. a lower tubular breech block member including: thereto Positioned at the lower end thereof; a d

i. means for connecting a lower end of said lower external threads at the lower end Portion tubular breech block member to the pipe section lllereof ll'ltemlpled along longitudinally exlendtherebelow; and l5 g p b. a lower tubular member, including:

i. means connecting a lower end of said lower tubular member to a pipe section therebelow;

ii. internal threads within the upper portion thereof;

iii. and at least one longitudinal groove below said internal threads;

iv. said internal threads being interrupted along longitudinally extending spaces and being arranged to matingly engage with said interrupted external threads of said upper tubular member;

v. whereby said upper and lower tubular members can be selectively connected or disconnected by rotational and longitudinal movement relative to each other;

e. a locking sleeve means, slidably disposed within said lower tubular member, including:

i. at least one upwardly projecting lug means, at-

ii. interrupted threads positioned at the upper portion thereof, said threads being interrupted along longitudinally extending spaces and being arranged to engage in breech block manner with said interrupted threads of said upper tubular breech block member whereby said upper and lower tubular members can be selectively connected or disconnected by rotational and longitudinal movement relative to each other;

c. locking sleeve means for locking said upper and lower breech block tubular members against relative rotation, when said tubular members are breech block engaged and said locking sleeve means is fully positioned at an uppermost location within one of said tubular members, for allowing relative rotation of said tubular members when said locking sleeve means is moved to a lower location andi for moving from said upperrgost loca z t0 tached thereto and positioned at the upper end sai ower ocation responsive to ownwar orce applied to said locking means; and tgg ggi g fgggf lii gg $213 i a dprolectmg p for maintaining, Said linking Sleeve means ii. at least one longitudinal spline means, attached ma groove in sai ower tu uar mem er,

rom rotatin within sai ower tubular mem er,

uppetmosf PQSMW to Said location affter but is free t5 move vertically between an upper g appgcfanon of at least Said predetermmed location where said upper and lower tubular ownwar orcemembers are locked against relative rotation by aliases: zszzpiaz e 2 means 0 sai 00 mg seeve means wit t e a. said upper tubular member including at least one downwardly projecting lug f Said upper tubular downwardly Projeclmg lug attached thereto and member and a lower location where said tubular positioned on the lower end thereof; members are unlocked; and

b. a locking sleeve slidably disposed within said lower means f maintaining Said locking Sleeve means tubular member having at least one p y P at said upper location until a predetermined force jecting lug attached thereto and positioned at the i i d thereto pp end thereof for engaging Sald downwardly 6. The releasable pipe connection of claim 5 wherein projecting lug of said upper tubular memb Said the means for maintaining said locking sleeve means at locking sleeve including at least one longitudinal said upper location until a predetermined downward spline attached thereto; and force is applied thereto comprises at least one shear pin aid lower tubular member including at least one connected between said locking sleeve means and said groove for matingly engaging said locking sleeve lower tubular member. spline so that said locking sleeve is prevented from 7. The releasable pipe connection of claim 6 wherein rotating within said lower tubular member, but is said locking sleeve means is further characterized to free to move between said upper location whereby include a seat means for sealingly receiving a release said upper and lower tubular members are locked plug, whereby a predetermined downward force can be against relative rotation and said lower location applied to said locking sleeve means by way of said rewhereby said tubular members are unlocked. lease plug.

3. The releasable pipe connector of claim 2 wherein 8. The releasable pipe connection of claim 7 wherein said locking sleeve means are further characterized to said release plug includes means for maintaining said include seat means for sealingly receiving a release plug release plug in sealing relationship to said seat means. by way of said upper tubular member. 

1. A releasable breech block pipe connector, for connecting a pipe section thereabove to a pipe section therebelow, which comprises: a. an upper tubular breech block member including: i. means for connecting an upper end of said upper tubular breech block member to the pipe section thereabove; and ii. interrupted threads positioned at the lower end thereof, said threads being interrupted along longitudinally extending spaces; b. a lower tubular breech block member including: i. means for connecting a lower end of said lower tubular breech block member to the pipe section therebelow; and ii. interrupted threads positioned at the upper portion thereof, said threads being interrupted along longitudinally extending spaces and being arranged to engage in breech block manner with said interrupted threads of said upper tubular breech block member whereby said upper and lower tubular members can be selectively connected or disconnected by rotational and longitudinal movement relative to each other; c. locking sleeve means for locking said upper and lower breech block tubular members against relAtive rotation, when said tubular members are breech block engaged and said locking sleeve means is fully positioned at an uppermost location within one of said tubular members, for allowing relative rotation of said tubular members when said locking sleeve means is moved to a lower location and for moving from said uppermost location to said lower location responsive to downward force applied to said locking means; and d. means for maintaining said locking sleeve means at said uppermost location until at least a predetermined downward force is applied to said locking means, said maintaining means adapted to allow movement of said locking sleeve means from said uppermost position to said lower location after only application of at least said predetermined downward force.
 2. The releasable pipe connector of claim 1 wherein said locking means comprises: a. said upper tubular member including at least one downwardly projecting lug attached thereto and positioned on the lower end thereof; b. a locking sleeve slidably disposed within said lower tubular member having at least one upwardly projecting lug attached thereto and positioned at the upper end thereof for engaging said downwardly projecting lug of said upper tubular member, said locking sleeve including at least one longitudinal spline attached thereto; and c. said lower tubular member including at least one groove for matingly engaging said locking sleeve spline so that said locking sleeve is prevented from rotating within said lower tubular member, but is free to move between said upper location whereby said upper and lower tubular members are locked against relative rotation and said lower location whereby said tubular members are unlocked.
 3. The releasable pipe connector of claim 2 wherein said locking sleeve means are further characterized to include seat means for sealingly receiving a release plug by way of said upper tubular member.
 4. The releasable pipe connector of claim 3 wherein the means for maintaining said locking sleeve means at said upper location until a predetermined downward force is applied thereto comprises at least one shear pin connected between said locking sleeve means and said lower tubular member.
 5. A releasable pipe connection which comprises: a. an upper tubular member, including: i. means connecting an upper end of said upper tubular member to a pipe section thereabove; ii. at least one downwardly projecting lug attached thereto positioned at the lower end thereof; and iii. external threads at the lower end portion thereof interrupted along longitudinally extending spaces; b. a lower tubular member, including: i. means connecting a lower end of said lower tubular member to a pipe section therebelow; ii. internal threads within the upper portion thereof; iii. and at least one longitudinal groove below said internal threads; iv. said internal threads being interrupted along longitudinally extending spaces and being arranged to matingly engage with said interrupted external threads of said upper tubular member; v. whereby said upper and lower tubular members can be selectively connected or disconnected by rotational and longitudinal movement relative to each other; c. a locking sleeve means, slidably disposed within said lower tubular member, including: i. at least one upwardly projecting lug means, attached thereto and positioned at the upper end thereof, for engaging said downwardly projecting lug of said upper tubular member, and ii. at least one longitudinal spline means, attached thereto, for matingly engaging with said longitudinal groove in said lower tubular member, iii. whereby said locking sleeve means is prevented from rotating within said lower tubular member, but is free to move vertically between an upper location where said upper and lower tubular members are locked against relative rotation by engagement of the upwardly projecting lug means of said locking sleeve means with thE downwardly projecting lug of said upper tubular member and a lower location where said tubular members are unlocked; and d. means for maintaining said locking sleeve means at said upper location until a predetermined force is applied thereto.
 6. The releasable pipe connection of claim 5 wherein the means for maintaining said locking sleeve means at said upper location until a predetermined downward force is applied thereto comprises at least one shear pin connected between said locking sleeve means and said lower tubular member.
 7. The releasable pipe connection of claim 6 wherein said locking sleeve means is further characterized to include a seat means for sealingly receiving a release plug, whereby a predetermined downward force can be applied to said locking sleeve means by way of said release plug.
 8. The releasable pipe connection of claim 7 wherein said release plug includes means for maintaining said release plug in sealing relationship to said seat means. 